1. Field of the Invention
The present invention relates generally to an information display apparatus, an information display method, and an information display system.
2. Description of the Related Art
Portable communication devices, such as notebook PCs (personal computers) and PDAs (personal digital assistants) have recently become popular. Very recently, generally speaking, participants of conferences or other events (hereafter conferences) bring their own portable communication devices into the conference. Presentations are facilitated by operating these portable communication devices.
For example, a presenter at a conference usually stores materials for his presentation in his own communication apparatus as electronic data. During the presentation, the electronic data stored in the presenter's communication apparatus is outputted by way of an information output apparatus, such as a projector, a television, a monitor, a speaker, or the like.
Generally speaking, the communication apparatus of the speaker is conventionally connected to the information output apparatus via a cable, such as, for example, a serial cable or a video cable.
Very recently, since wireless communication devices have become more popular, the communication apparatus of the presenter may be wirelessly connected to the information output apparatus. Using a wireless connection, cumbersome cables are no longer required, and the communication apparatus may be positioned at a variety of locations.
However, there is a risk when using wireless connections that a third party having ill will may intentionally disturb the progress of the presentation by connecting his own communication apparatus to the information output apparatus. Additionally, a third party may acquire data transmitted/received between the communication apparatus of the presenter and the information output apparatus in an unfair manner. When the presenter's communication apparatus is connected to the information output device by a cable, this risk is not present.
To solve this security problem, an encryption idea may be conceived. That is, the data transmitted/received between the communication apparatus of the presenter and the information output apparatus may be encrypted. For instance, an encryption key may be distributed to authorized participants for a conference.
In a location where a conference is held, a presenter having an encryption key can encrypt data via a communication apparatus and transmit the encrypted data to an information output apparatus, which can decode the encrypted data to output the decoded data. Also, other participants having the encryption key may decode the data transmitted by the presenter using their own communication devices, so that these participants may view or hear the content of the presentation.
However, since the encryption keys are previously distributed, it is possible that the encryption keys might be given to an unauthorized person. Also, if an authorized participant forgets the encryption key, this person cannot make the presentation, cannot view the content of the presentation, or cannot hear the presentation. Thus, it is evident that distributing encryption keys in advance has disadvantages.
Patent Publication No. 2002-218420 (Kokai) describes a potential solution for when a third party having good will mistakenly transmits data and interferes with a presentation made by another person. For example, a method may be conceived in which a participant inputs discrimination information for an information output apparatus from which image information is desired. This communication apparatus transmits both the entered discrimination information and image information desired from an information output apparatus to the information output apparatus from which the image information is sought to be outputted. This information output apparatus outputs the received image information only when the received discrimination information coincides with the user's own discrimination information.
This method prevents against accidental interference by a third party. However, since the discrimination information is directly transmitted without being protected by encryption, it is possible that the discrimination information might be stolen by unauthorized third parties. As a consequence, this method cannot prevent access by malicious third parties.
On the other hand, participants in a conference are often acquainted with each other. Even when someone who is not acquainted with the other participants is present, the identity of the participant may be confirmed by employing an authentication tool, such as digital authentication or an identification card. In such a case, a suspicious character located in an assembly hall of a conference may be identified, and may be expelled from the assembly hall.